Bathroom scale



H. L. MATTSON BATHROOM SCALE July 17, 1962 Filed April 14, 1960 Harry I.Matso'z United States Patent Ofiiice 3,044,564 Patented July 17, 1962&044564 BATHROUM SCALE Harry L. Mattson, Rockford, Ill., assignor to TheBrearley Company, Rockfo'd, lil., a corporation of Illinois Filed Apr.14, 1960, Ser. No. 22,276 7 Claims. (CI. 177--230) all Operatingconditions and transmitting a corresponding amount of movement to theweight indicating means so as to give an accurate reading. With thatConstruction, inasmuch as the arcuate movement of the outer end of themain lever is translated through the pin in the center of the springinto a corresponding arcuate'rnovement of one arm of a bell-cr anklever, the other arm of which in the arcuate movement of its free endtranslates the movement into linear movement of the rack that operatesthe pinion connected to the weight indicating dial, it follows that whatare known as arc losses in the trade are substantially entirelyeliminated, to the extent that error in weight indications ispractically negligible, amounting to less than /s of 1% by actual tests.

According to the present invention, a cylindrical cup is mounted on thefollower pin in concentric relationship thereto and guided loosely byits cylindrical slide walls inside the spring, so that the follower pin,which has its conically pointed lower end fulcrumed in a conicaldepression provided on the lever, is always assured of remaining in the,correct operative relationship to said lever and spring under allOperating conditions and, therefore, a correct weight indication isalways assured, there being no danger of the pointed lower end of thefollower pin ever becoming displaced from-operative relationship to thelever.

The invention is illustrated in the accompanying drawing, in which:

PIG. l is a longitudinal section on a reduced scale of a bathroom scaleembodying the improvements of my invention;

FIG. 2 is an enlarged section corresponding to the front end portion ofFIG. 1 to better illustrate the present improvements, and

FiG. 3 is a cross-section on the line 3-3 of FIG. 2.

The same reference numerals are applied to corresponding parts in thesethree views. i

Referring to the drawing, the bathroom scale illustrated is similar tothat disclosed in Prov-i Patents 2,667,3 87 and 2,668,045, the referencenumeral 12 designating the generally rectangular sheet metal base orbottom pan thereof, and 13 the generally rectangular sheet metalplatform supported on said base by means of two stamped sheet metallevers 14 and 15, lever 14 being supported on the base 12 on a pair offulcrums 16 and carrying a pair of hangers 17 on which rest a pair ofdownwardly projecting legs 13 for support of the rear end portion of theplatform 13, In asimilar manner, lever 15 is supported on the base 12 onanother pair of fulcrums 16' and carries a pair of hangers 17' on whichrest another pair of downwardly projecting legs 18', like the legs 18,for support of the front end portion of the platform 13. A coiledtension spring 19 serves as the weighing spring and is Suspended abovethe front end portion of the base 12 for suspension of the front endportion 20 of the lever 14 to resist downward deflection thereof underthe weight imposed thereon when a person stands on the platform 13, aswhen weighing himself. Weight imposed on the platform 13 is transmitteddirectly to the lever 14 through legs 18 provided under the rear endportion of the platform, butn the weight imposcd by the front endportion of the platform 13 on lever 15 is transmitted through said leverto the middle portion of lever 14 at the rear end of the lever 15, wherethere is a hanger 21 pivotally supported at its coaxially aligned endson the lever 14 and having the notched lower end of a downwardly bentlug 22 on the rear end portion of lever 15 engaged in the downwardlyoifset crank pin portion provided in the middle of said hanger 21. Atubular screw 25, on the headed lower end 26 of which a cupped Washer 27is swiveiled and adjustably connected with the upper end portion ofspring 19 in the usual way, as indicated at 28, is Suspended on ahand-nut 29 accessible for manual adjustnent through an opening 30provided in a cover plate 31 mounted on top of the platform 13 at thefront end thereof, the nut 29 being adjusted one way or the other toadjusted the spring 19 up or down in order to set the scale back to zerowhen and if it gets out of adjustment and requires re-setting. It is thedownward deflection of the front end portion 20 of the lever 14 againstthe resistance of spring 19 that is used to cause rotation of the Weightindicatng dial` 32. This dial is carried on a vertical shaft 33supported for rotation over the center portion of the base 12, and apinion 34 is provided on the lower end portion thereof for transmittingrotation thereto. A rack 35 is free to float in a guide 35' (so that itcan rise and fall in following the arc of travel of the lower end oflever 38) and meshes with the pinion 34 and is biased toward it by alight coiled tension spring 36 that is attached at one end to the rearend of the rack and at its other end to a lug 37 provided on the rearend portion of lever 14. The spring 36, in addition to holding the rack35 resiliently in engagement with pinion 34, exerts enough pullrearwardly on the rack to operate the dial 32 whenever the rack is freeto move, as when the lever 14 is given downward deflection in a weighingoperation, a bell-crank lever 38 'pivotally connected at 39 to the frontend of rack 35 being then allowed to oscillate from its zero positionthrough an angle, the size of which is proportionate to the amount ofextension of spring 19 and downward deflection of lever 14, so as tocause rotation of dial 32 through a proportionate angularity andaccordingly indicate accurately the weight of the person standing on thescale. Bell-crank lever 38 is pivoted with respect to the base 12 on ahorizontal axis, as indicated at 40, a horizontally extending pinproviding this pivot, the pin extending through laterally spacedregistering holes provided in laterally spaced portions of said leverand being supported in a br acket 41 that is mounted on top of the frontend portion'42 of an elongated sheet metal channel-shaped member 43 thatserves also to support the dial and pinion on its rear end and itsmounted by means of its web portion 44 on the front middle portion ofthe base 12, in accordance with Provi et al., Patent No. 2,875,999.

A circular hole 49 in the transverse horizontal web portion 56 ofbracket 41 receives the tapered port-lon 51 of the hand-mut 29 forsupport of the spring 19 and suspension of the front end portion 20 oflever 14. As described in the copending Provi application mentionedabove, it is due to the fact that the downward deflection of the frontend portion 20 of lever 14 against the resistance of spring 19 isreflected so accurately by endwise movement of a follower pin 52extending through the tubular screw 25 and hence disposed accurately onthe center line of the spring 19 that such close accuracy in weightreadings on dial 32 is obtained. The lower end of the pin 52 has to moveaccurately With the loop 53 on the lower end of the spring 19 that isreceived in the slot 54 in the front end portion Zt* of the lever 14 byfulcruming of the pin on the front end portion 26 of lever 14, butinasmuch as this front end portion of the sheet metal lever 14 isusually bent so as to be disposed edgewise in the vertical plane of thepin 52 this has presented a problem, because, obviously, such slightmisalignment as could occur in the quantity production of the Scales ormight arise in shipment because of rough handling of a scale, causing acertain amount of lateral displacement of the one part With respect tothe other, could result in the conically pointed lower end of the pin 52no longer remaining fulcrumed on top of the front end portion 20 byreason of the point riding oif one side or the other of said endportion, and, of course, it is important that the lower end of the pin52 be conically pointed, as at 57, for a low friction fulcrum andaccordingly greater accuracy in the indicated weight reading. The upperend 58 of the pin is also conically'pointed for this same reason, thatend being fulcrumed in a conical recess 59 in the forwardly extendingarm 69 of the bell-crank lever 38. The pin 52 has a loose fit in thetubular screw 25, as indicated by the clearance 61 in FIGS. 2 and 3, sothat there is no danger of friction interfering with the freedom ofendwise movement of the pin and being reected by errors in the indicatedweight.

In accordance with my invention, a cylindrical stamped sheet metal cup62 is mounted on the pin 52 in concentric 'elationship thereto, as by apress fit of the pin in a center hole 63 in the bottom wall 64, the pin52 being thereby guided to a large extent against displacement laterallyfrom operative relationship to the lever 14 and spring 19 by abutment ofthe side walls 65 of the cup 62 on either side with the coils o-f thespring 19 and accordingly assured of remaining in proper fulcrumengagement With the top of the front end portion 28 of lever 14. The pin52 is maintained on the center line of spring 19 by its conicallypointed lower end 57 engaging in the center of the conically shapeddepression 66 provided in the top of the front end portion 2@ of lever14, similarly as the conically pointed upper end 58 of the pin engagesin the center of the conical depression 59 in arm &ti of lever Inoperation, the Washer 27 Will be adjusted With respect to spring 19 in aseparate operation before this assernbly is assembled in the scale.Then, in the calibration of the scale, the Washer 27 Will be adjustedslightly up or down on the spring 19 as required. Thereafter, the userneed adjust only the hand-nut 29 occasionally, whenever the scale doesnot happen to return to zero after use. No other adjustments arenecessary. In the event a person jumps on the platform 13, no harm canbe done, inasmuch as the bell-crank lever 38 is always operated gentlyin response only to the light tension of spring 36, regardless of howsuddenly and ronghly the lever 14 may be deflected downwardly. Wheneverthe follower pin 52 is subjected to jostling, as in shipment of thescale or when a person jumps on the platform 13, there is no danger Withthe present Construction of the pin 52 becoming displaced from itsproper operative relationship between the end 6@ of lever 38 and thefront end portion 20 of lever 14, because the cup 62 is guided by itsloose telcscoping relationship to 'the spring 19 to prevent lateraldisplacement of the pin 52 from operative relationship to the lever Mand spring 19, while the conical lower end 57 of the pin is alwaysguided back to its central position in the conical depression 66 in thefront end portion 2@ of lever 14, similarly as the pin's conical upperend 58 is always guided back to its central position in the conicaldepression 59 in arm sa, so that the pin 52 is thereby always maintainedon the center line of the spring 19 to operate as intended and reflectaccurately the amount of extension of the spring 19 in each weighingoperation and accordingly cause the scale to give closely accurateweight readings.

It is believed the foregoing description conveys a good 4; Understandingof the obects and advantages of my invention. The appended elaiins havebeen drawn to cover all legitirnate modifications and adaptations.

I claim:

1. A weighing scale comprising `a base, weighing levers fulcrumedthereon, a platform movably supported above said base on said levers, acoiled tension spring serving as the weighing spring Suspended on saidbase and connected with said weighing levers to resist downwarddefiection thereof under Weight applied to the platform, weightindicating means, means for Operating said weight indicating meansmovable in response to downward deflection of said weighing levers, saidOperating means including a vertical follower pin fulcrumed at its lowerend on one of said weighing levers to which the lower end of the springis connected, said pin extending through said spring and disposed on thecenter line thereof and arranged to move endwise the same distance asthe spring is extended in each weighing operation to operate the weightindicating means accordingly and give an accurate Weight reading, and acylindrical guide member carried on said pin intermediate the endsthereof and disposed intermediate the ends of said spring in concentricrelationship to said pin and maintained -approximately in concentricrelationship to the spring by a loose telescoping fit therein andmovable vertically with the pin in the spring's extension in weighing soas to keep the pin approxirnately on the center line of the spring formore uniforrnly accurate weighing.

2. A weighing scale as set forth in claim 1 wherein said cylindricalguide member comprises a cup having side walls which are cylindrical andare in telescoping relationship to the spring, and =a transverse wall inthe center of which an opening is provided in which an intermediateportion of the length of said pin is entered and fixed so that said pinis centered relative to the spring.

3. A weighing scale as set forth in claim 1 wherein the pin is furthermaintained on the longitudinal center line of the spring by engagementof the lower end of said pin in a conical depression provided on thatone of said weighing levers to the end of which the spring is connectedfor spring suspension of the weighing levers, the lower end of said pinbeing conically pointed for point engagement in the center of saidconical depression.

4. A weighing scale comprising a base, weighing levers fulcrurnedthereon, a platform movably supported above said base on said levers, acoiled tension spring serving as the weighing spring Suspended on saidbase and connected With said weighing levers to resist downwarddeflection thereof under weight applied to the platform, weightindicating means, a bell-crank lever pivoted With respect to said basehaving one arm thereof pivotally connected with said weight indcatingmeans to operate it and having the other arin thereof extending oversaid spring, a follower pin fulcrumed at its lower end on one of saidweighing levers to which the lower end of the spring is connected, saidpin extending through said spring and disposed on the center linethereof operatively connecting said last mentioned arm with theextensible end of said coiled spring and movable endwise the samedistance as said spring is extended in each weighing operation, wherebyto operate the weight indicating mean-s so as to give an accurate Weightindication, and a cylindrical guide member carried on said pinintermediate the ends thereof and disposed intermediate the ends of saidspring in concentric relationship to said pin and maintainedapproximately in concentric relationship to the spring by a loosetelescoping fit therein and movable vertically with the pin in thespringh extension in weighing so as to keep the pin approximately on thecenter line of the spring for more uniformly accurate weighing.

5. A weighing scale as set forth in claim 4 wherein said cylindricalguide member comprises a cup having side walls which are cylindrical andare in telescoping reconnected for spring suspension of the weghinglevers, 10

the lower end of said pin being conically pointed for point engagenentin the center of said conical depression.

7. A Weighing scale as set forth in claim 4 Wherein the overhanging armof said bell-crank lever has a conical depression open to the undersidethereof, and the upper end of said pin is conically pointed and receivedin the apex of said depression.

No references cited.

